In recent years, a transmission system that conducts a television conference via a communication network, for example the Internet, have spread. In such a transmission conference system, image data and audio data are transmitted/received among a plurality of transmission terminals to realize the television conference.
The enhancement of broadband environment in recent years has allowed for the transmission/reception of high-quality image data and high-quality voice data. Therefore, one can recognize a state of the other one in the telephone conference more easily and have a much better communication through conversation.
When the telephone conference is held by using a transmission terminal, the participants in the telephone conference sometimes uses an external input device, for example an individual PC (Personal Computer), in addition to the transmission terminal, in order to have a discussion or the like with the other-one who attends the conference, by displaying an image of conference materials or the like on a display of the external input device. In this case, conventionally, a conventional external input device has transmitted, to a transmission terminal used by the other one who attends the telephone conference via the communication network, display data generating the image of the conference materials or the like to be displayed on the display of the external input device.
Accordingly, the participants in the telephone conference can hear a voice of the other one who attends the telephone conference and see an image of his or her face, which are generated by the voice data and the image data transmitted/received through the transmission terminal while the conference is held. Also, the participants in the telephone conference can share the image of the display data that is displayed on the display of the external input device with the other one who attends the telephone conference.
Another technology pertaining to sharing the image of the display data among transmission terminals appears, for example, Japanese Patent No. 4738628, which is incorporated herein by reference in its entirety. A data conference system disclosed in the Patent Literature includes a terminal and a remote terminal connected to the terminal. In the data conference system disclosed in the Patent Literature, an image displayed on a display screen by an application program used by the terminal is captured by a graphical device interface and transmitted to the remote terminal, so that the image displayed on the display screen is shared with the terminal and the remote terminal. Display resolution information of the remote terminal is stored in the terminal, so that the resolution of the captured data is converted based on the display resolution information for the entire display screen before the captured data is transmitted to the remote terminal.
However, a conventionally known external input device is imposed a limitation on the resolution of an image that is supported at a transmission terminal. Therefore, when a user desires to share the image of the display data, the resolution of the external input device need to be modified so as to conform with the resolution supported by the transmission terminal. This disadvantageously leads a lot of time and effort for operating the external input device.
A similar problem can occur in the data conference system described in the Patent Literature. In a case where data for display in the external input device connected to his/her own terminal is transmitted to the other terminal, a user is required to change the setting for the resolution of the external input device, so that the user suffers from the burden on operation.
The present invention has been created in consideration of the aforementioned conventional problems. An object of the present invention is to reduce the burden of user operation by enabling the image of the display data to be shared with another transmission terminal without requiring the change of the resolution in the external input device by the user.